Apparatus for the manufacture of polyurethane plastics



Get. 17, 1967 P. HOPPE ETAL. 3,347,529

APPARATUS FOR THE MANUFACTURE OF POLYURETHANE PLASTICS Original FiledAug. 8, 1955 3 Sheets-Sheet 1 FIG. 3.

PE 7' E1? HOPPE GOH/VEL IUS MUHLHAUSE/V 8 KARL BREE R INVENTORS km Qwd,

ORNEYS Oct. 17, 1967 P. HOPPE ETAL 3,347,529

APPARATUS FOR THE MANUFACTURE OF POLYURETHANE PLASTICS Original FiledAug. 8, 1955 3 Sheets-Sheet 2 PE 7' E HOPPE ERM/l/V WE/NBRE/V/VE/f?COR/VEL/US MUHL HAUSE/V 8 2 KARL BREE/7 INVENTORS ATTORNEYS Oct. 17,1987 P. HOPPE ETAL 3,347,529

APPARATUS FOR THE MANUFACTURE OF POLYURETHANE PLASTICS Original FiledAug. 8, 195 5 5 Sheets-Sheet 5 FIG. FIG. 9.

FIG. 1/. FIG. 12.

PE 75/? HOPPE ERWl/V WE/IVBRE/V/VER COR/VEL/US MUHLHAUSEN 8 KARL BRE Ef? INVENTORS ORNEYS United States Patent Ofi 3,347,529 Patented Get. I7,19%? ice 3,347,529 APPARATUS FOR THE MANUFACTURE OF POLYURETHANEPLASTICS Peter Hoppe, Troisedorf, Erwin Weinbrenner and CorneliusMuhlhausen, Leverkuseu-Bayerwerk, and Karl Breer, Cologne-Flittard,Germany, assignors, by direct This application is a division of ourcopending application Ser. No. 527,106, filed Aug. 8, 1955, now US.Patent No 2,764,565, issued Sept. 25, 1956, which in turn is acontinuation-in-part of our copending application Ser. No. 327,522,filed Dec. 23, 1952, now abandoned.

This invention relates to an improved apparatus for the manufacture ofporous and homogeneous polyurethane plastics of rigid, semi-rigid orelastic consistency.

The formation of polyurethane plastics involves essentially apolyaddition between polyesters and polyisocyanates although, incompounding to obtain the final products, other materials, such asfillers, accelerators and/ or cross-linking agents are desirably added.When foamed products are sought, water or an aqueous solution may alsobe employed. The plastic materials having a specific gravity of about0.021.0 are porous and are classified as foamed plastics; those whichhave a specific gravity of about 1.01.4 are non-porous and aredesignated as homogeneous plastics.

The invention involves a complex series of physicalchemical reactionswherein heat is evolved, viscosity changes are efi'ected and rapid anduniform mixing of materials of widely different viscosities isnecessary. By proceeding according to the present invention, applicantshave been able to control these conditions to a degree heretoforeunattainable and products may be produced which are not subject to thedeficiencies of the prior art but are uniform in texture andreproducible in quality. Thus, in contrast to the prior art products,the plastics of the present invention are more uniform in appearance,have a more regular cell structure and are reproducible to a highdegree. Shrinkage after curing (i.e., within a few minutes after theinitial foam rise has been completed) which is a primary problem in themanufacture of light foams is held to a minimum as a result of thepresent invention. Whereas it was considered essential to mix thecomponents necessary for formation of the polyurethane plastics forseveral minutes in the prior art processes, the process carried out inthe apparatus invented normally requires a mixing time of the order 0.5to 25 seconds.

In the formation of polyurethane plastics by the instant invention, thecondensation of polyesters and polyisocyanates is carried out in thepresence of an activator mixture (the term activator mixture, as usedherein, is meant to include at least one accelerator and/or crosslinkingagent to which may be added water or an aqueous solution, if necessary).The activator mixture is introduced into the reaction mixture in a finestate of subdivision at an elevated pressure substantially higher thanthat of the reactant mixture. Mixing of the components is effected in anenclosed vessel for a short period of time, and the resultant product isdischarged while still in the liquid state and before any substantialliberation of gases has taken place. It is preferred to introduce theactivator mixture into the polyester-polyisocyanate intermittently formost effective operation. However, it is possible to control conditionsso that, in certain operations, a continuous feed for this component maybe utilized. The activator mixture is introduced into thepolyester-polyisocyanate shortly before the polyaddition reaction takesplace; and the crosslinking action and/ or foaming of the polyurethanesthereby becomes one of extremely high intensity and yields a morehomogeneous product for use in the manufacture of moldings, cavityfillings, coatings, piece goods, etc.

The expression component influencing the reaction, as hereinafter usedcomprises the activator mixture defined above and/or any other materialor combination of materials having a catalytic effect on the reactionbetween the polyisocyanate and the other reactants used in themanufacture of homogeneous and porous plastics.

Thus, in the apparatus of the invention, an hydroxy polyester, apolyisocyanate and a component influencing the reaction are broughttogether in a mixing zone, with at least the reaction influencingcomponent being injected at a pressure substantially higher than theback pressure in the mixing zone and then discharging the resultinguniform mixture of ingredients in the liquid state from said zone. Thepolyester and polyisocyanate may be introduced into the mixing zoneeither separately or in admixture;

and the reaction influencing component may be introduced separately, orif desired, in admixture with the polyester or the polyisocyanateprovided the latter is used in a blocked or inactive form whichliberates the polyisocyanate on heating, Polyisocyanate-rnodifiedpolyesters, poiyesteramides, polyisocyanate-modified polyesteramides,alkylene glycols, polyisocyanate-modified alkylene glycols,polyoxyalkylene glycols and polyisocyanate-modified polyoxyalkyleneglycols may also be utilized.

The polyesters used for the production of the polyurethanes having aspecific gravity in the range of about 0.02l.4 (i.e. those of rigid,semi-rigid or elastic consistency) may be branched and/ or linear. Thus,the useful polyesters and/or polyesteramides may include those obtainedby condensing any polybasic (preferably dibasic carboxylic) organicacid, such as adipic, sebacic, 6-aminocaproic, phthalic, isophthalic,terphthalic, oxalic, malonic, succinic, maleic, cyclohexane-1,2dicarboxylic, cyclohexane 1,4 dicarboxylic polyacrylic, naphthalene-1,2-dicarboxylic, fumaric, itaconic, etc., with polyalcohols such asethylene glycol, diethylene glycol, pentaglycol, glycerol, sorbitol,triethanolamine, di-(fi-hydroxyethyl) ether, etc. and/or amino-alcoholssuch as ethanolamine, S-aminopropanol, 4-aminopropanol, S-aminopentanol1, G-aminohexanol, 10,-aminodecan0l, 6-amino-5 methylhexanol 1,p-hydroxymethylbenzylamine, etc.; and with mixtures of the abovepolyalcohols and amines (ethylene diamine, hexamethylene diamine,3-methylhexamethylene diamine, decamethylene diamine andrn-phenylenediamine, etc.) and/or amino-alcohols, etc. In theesterification, the acid per se may be used for condensation or, wheredesirable, equivalent components, such as the acid halide or anhydridemay be used.

The alkylene glycols and polyoxyalkylene glycols used in the practice ofthe invention may comprise ethylene glycol, propylene glycol, butyleneglycol-2,3; butylene glycol-1,3; Z-methyl pentanediol-2,4;2-ethylhexanediol 1,3; hexamethylene glycol, styrene glycol anddecamethylene glycol, etc. and diethylene glycol, triethylene glycol,tetraethylene glycol, polyethylene glycols 200, 400 and 600 etc.dipropylene glycol, tripropylene glycol, polypropylene glycols 400, 750,1200 and 2000, etc.

Broadly, any of the prior art polyesters, polyisocyanatemodifiedpolyesters, polyesteramides, polyisocyanatemodified polyesteramides,alkylene glycols, polyisocyahate-modified alkylene glycols,polyoxyalkylene glycols a) and polyisocyanate-modified polyoxyalkyleneglycols, etc. having free reactive hydrogen atoms, free reactivecarboxylic and/or especially hydroxyl groups may be employed in theapparatus of the invention and condensed in said apparatus. Moreover,any organic compound containing at least two radicals selected from theclass consisting of hydroxyl and carboxyl groups may be employed in thepractice of the invention.

The organic polyisocyanates useful in the practice of the inventioninclude ethylene 'diisocyanate, ethylidene diisocyanate,propylene-l,2-diisocyanate, butylene-l,3-diisocyanate,hexylene-l,6-diisocyanate, cyclohexylene-l,-2 diisocyanate,m-phenylenediisocyanate, 2,4-toluylene diisocyanate, 1,6-toluylene diisocyanate,3,3'-dimethyl 4,4'- biphenylene diisocyanate,3,3'-dimethoxy-4,4-biphenylene diisocyanate,3,3-diphenyl-4,4-biphenylene diisocyanate, 4,4-biphenylene diisocyanate,3,3'-dichloro-4,4- biphenylene diisocyanate, triphenylmethanetriisocyanate, 1,5-naphthalene diisocyanate or polyisocyanates in ablocked or inactive form such as the bis-phenyl carbamates of toluylenediisocyanate, p,p-diphenylmethane diisocyanate, p-phenylene diisocyanateand 1,5-naphthal ene diisocyanate, etc.

The activator mixture is made up of at least one crosslinking agentand/or an accelerator and may contain, if desired, added water or anaqueous solution. The addi: tion of such an activator mixture to themixture of polyisocyanatesl and polyesters initiates the cross-linkingaction needed to obtain homogeneous plastics or the cross-linking andfoaming action necessary to obtain foam plastics. Useful cross-linkingagents include water or aqueous solutions for foamed plastics and thepolyalcohols, such as ethylene glycol, propylene glycol, butyl eneglycol, diethylene glycol, triethylene glycol, glycerol etc. fornon-porous plastics; and useful accelerators include the tertiary amines(either individually or in mixtures) such as. dimethylhexahydroaniline,diethylhexahydroaniline, reaction products of N,N'-diethylaminoethanoland phenylisocyanate', ester-amines, etc. Also sodium phenolates, addedwith suitable plasticizers, may be employed in the manufacture of foamedproducts.

As has been indicated above, it is desirable and advantageous tointroduce the activator mixture, in a very fine state of subdivision andunder relatively high pressure, into, the polyesterapolyisocanatemixture before polyaddition occurs. The required amount of activatormixture, which is small compared with the other components, is injectedinto the mixture of isocyanate and polyester under high pressure andpreferably by means of one or more injection nozzles and intermittentlyoperating pumps, for instance by means of the devices hereinafterdescribed.

According to one embodiment of'the invention, the activator mixture isintroduced or injected intermittently into a continuous stream ofpolyisocyanate and polyester, which stream is advanced by standard meanssuch as a gear pump system. To insure adequate penetration of theactivator mixture into the reaction mixture, the intermittent feedenters througha nozzle or nozzles at a relatively high pressure andfrequency.

To carry out the above described process, an apparatus is employed whichincludes an enclosed reaction or mixing device, means for inducingcontinuous flow of initial materials such as the isocyanate-polyestermixture and means for intermittently introducing the activator mixtureinto the reaction mixture at elevated pressure. More particularly, theapparatus preferably includes at least one injection device to effectthe proper intermittent feed of the activator mixture through a nozzleor another suitable device into the continuous stream of the initialmaterials.

In a preferred embodiment of the invention, the tworeaction componentsof the reaction mixture, namely at least one diisocyanate and at leastone polyester containing hydroxyl groups, are conveyed separately to areaction'or mixing device into which theyare injected under pressurethrough separate nozzles or a common mixing nozzle and the activatormixture is either conveyed separately to the reaction device andinjected into it under pressure through a separate nozzle or a commonmixing nozzle.

The activator mixture may advantageously be conveyed to the reaction ormixing device in admixture with the polyester component, the mixturebeing injected under pressure into the device either through a commonmixing nozzle with the isocyanate component or through a separatenozzle. Similarly, in some operations, particularly in the production ofhomogeneous plastics, the ac,- tivator mixture may be conveyed to thereaction or mixing device in admixture with the polyisocyanate if thelatter is employed in a blocked or inactive form which liberates thepolyisocyanate on heating.

In the practice of the invention in its preferred form, the componentsemployed in the manufacture of the plastic are forced into a commonreaction or mixing device by means of pumps. One of the pumps operatescontinuously while the other pumps operate intermittently;

all of the pumps are connected to the reaction or mixing device intowhich one component is introduced continuously while the activatormixture or preferably the activator mixture and the polyisocyanate areintroduced intermittently. The components conveyed by the pumps areintroduced by means of nozzles into the reaction or mixing device whichhas outlet means through which the final mixture is discharged in theliquid state.

Broadly stated, the apparatus of the invention comprises, incombination, an enclosed mixer and means through which the components(i.e. polyester containing free hydroxyl groups, vpolyisocyanate andreaction influencing component) used in the manufacture of the plasticsare brought together in said mixer, at least one of said meanscomprising an injector operating at a pressure substantially higher thanthat in said mixer, and outlet means through which the final uniformmixture of components is discharged in the liquid state.

More specifically, the apparatus for carrying out the process of theinvention comprises, in combination, an enclosed mixer, means to effecta continuous flow of initial materials (polyiso-cyanate and polyesteror, polyisocyanate-modified polyester) to the mixer, means for feedingthe activator mixture and/ or polyisocyanate and means forintermittently injecting the, activator mixture and/or polyisocyante inprecise quantities into a continous stream of the initial materials bymeans of at least one injection nozzle. Still more specifically, theapparatus includes a similar combination of elements together with meansfor separately and intermittently injecting the polyisocyanate and theactivator mixture under pressure into a continuous stream of the initialmaterial by means of injection nozzles.

The initial material or materials and the accelerator mixture aregenerally stored in tanks and are conveyed to the reaction or mixingdevice by means of pumps which, as indicated above, operate continuouslybut preferably intermittently in the case of the accelerator and/or thepolyisocyante. Any other standard method of storing andtransferring thematerials to the reaction or mixing device may be used.

The reaction or mixing device may contain separate compartments orchambers for injection of the reaction components and mixing. It ispossible, however, to arrange the device so that' both injection andmixing are carried out in a single compartment.

In the single chamber apparatus, the components conveyed by the pumpsare fed (the polyester preferably by continuous flow; the acceleratormixture and polyisocyanate preferably by intermittent injection) throughnozzles into a chamber equipped with stirring means (e.g. a mechanicalstirrer) as well as outlet means through which the final mixture isdischarged in the liquid state. In

another embodiment of the single chamber apparatus (see FIG. 3), thecomponents conveyed by the pumps are forced (the mixture ofpolyisocyanate and polyester in continuous flow and the acceleratormixture by intermittent injection) through nozzles into an injectionchamber provided with outlet means through which the final mixture isdischarged in the liquid state.

Where a 2-compartment device is used, one or more of the reactioncomponents required to form the desired plastic is introduced into theinjection chamber continuously while another component including theactivator mixture is intermittently injected into the continuous flow ofthe other components. Further mixing is then effected in a separatechamber by a desirable stirring means. According to one embodiment ofthe two chamber apparatus of the invention, the reaction or mixingdevice is divided by means of a nozzle plate into the injection chamberwherein the components are added and partially mixed and the mixingchamber wherein a more thorough mixing is effected. Any suitablestirring means may be used for this purpose. Thus, the mixing chambermay be provided with a tangential air feed connection through whichcompressed air is introduced into the mixing chamber to effect aturbulent flow and thorough mixing of the com ponents. Alternatively theapparatus may be divided by a nozzle plate into one compartment equippedwith a mechanical stirrer and another compartment provided with atangential air pipe connection for compressed air stirring.

The mixing time may be varied depending on the proportions and characterof the components employed as well as the type or plastic desired.Normally the mixing time is in the range of 0.5-25 seconds, althoughlonger or even shorter mixing periods may in some cases be desirable.The final reaction mixture, in the liquid state, may be treated invarious manners. For example, it may be passed onto a screw conveyerwhich forces the mixture through appropriately shaped nozzles to producemoldings of any desired design or insulating coverings for cables.Sometimes it is desirable to complete and/or accelerate the reaction ofthe liquid mixture issuing from the mixing chamber by heating. And this,of course may be done.

To the polyisocyanates one may add, in anhydrous condition, oils such asparafiiu oils (or other mineral oils) or surface-active substances toserve as activators for facilitating the feeding of the isocyanate. Suchoils may also be added to one or more of the other components used inthe formation of the plastics. These oils affect the porosity and/ordensity of the final product, which may be varied by varying thequantity of anhydrous oil added.

For continuous or conveyer belt manufacture of plastics, foamed productsor foils, the apparatus of the invention may be made up essentially ofstorage means (i.e. a storage tank) and a metering pump mounted on astationary support; and two similar storage means attached to meteringpumps mounted on an oscillating casting carriage which movestransversely to the conveyer belt. The components are injected throughnozzles by means of the pumps into the reaction or mixing device whichis mounted on the oscillating casting carriage.

For the production of foils the carriage moves transversely to theconveyer belt which slowly travels transversely to the moving directionof the casting carriage.

For the production of moldings the liquid mixture issuing from themixing chamber is cast into molds arranged and positioned on aturntable. The discharge of the mixture from the mixing chamber iscontrolled and adjusted in proper relation to the travelling velocity ofthe molds. In the continuous manufacture of profile cords or hollowarticles for the coating of wire or similar hollow articles the mixturesissuing from the mixing chamber is introduced into a conveyor screwwhich forces the almost completely reacted material throughappropriately shaped profile nozzles. After issuing from the mixingchamber, the material is passed into a chamber where it is hardened bycompleting the reaction. The product is then wound up on a roller.

The apparatus according to the invention can be adapted for instance forthe manufacture of porous and homogeneous plastics having a basis ofpolyurethanes. The apparatus for carrying into effect this embodiment ofthe invention consists essentially of a pump for inducing continuousflow of the initial material, e.g. a mixture of a polyisocyanate and apolyester, and another pump intermittently feeding the activatorcomponent, e.g. tertiary amines, into the continuous stream of theinitial material. The continuous flow of the initial material and theintermittent How of the accelerating liquid are contacted in thereaction or mixing device into which both streams are admittedseparately through nozzles. The apparatus may also be provided withthree pumps, one of these pumps inducing a continuous flow of thepolyester component, another pump intermittently feeding the isocyanatecomponent while the third pump intermittently feeds the activatorcomponent under high pressures. An important feature of the inventionresides in the manner in which the activator mixture is added to theremaining components used to form the plastics. The activator mixture isforced into the polyester stream (mixed with the polyisocyanate ifdesired) at a relatively high velocity so that it will adequatelypenetrate the high viscosity polyesterand form a uniform product. Thisis effected by means of an injection nozzzlc through which the activatormixture is introduced at a pressure substantially in the range of about300 p.s.i. to about 15000 p.s.i. and preferably within the range ofabout 1200 p.s.i. to about 5250 p.s.i.

In its broadest aspect, the invention, contemplates the use of injectionpressures which are higher and preferably substantially higher than theback pressure within the reaction or mixing device. Normally, the backpressure within the device is of the order of from 45 p.s.i. to p.s.i.depending upon the viscosity of the material and the size of thedischarge outlet. In the case of low viscosity materials, the backpressure may drop to as low as 17 p.s.i., but with more highly viscousmaterials, it may increase to much higher values than are normallyencountered.

Thus, in the case of low viscosity materials, the injection pressure mayfall as low as about 19 p.s.i. or in the case of moderately viscousmaterials it may drop to a value of about 47 p.s.i. to 77 p.s.i. Underthese conditions substantially improved results over mechanical mixingare obtained, but such low pressures are not the equivalent of 300p.s.i. and higher pressures since pressures of the latter order ofmagnitude result in more rapid and efiicient mixing and products moreuniform in texture and reproducible in character. Apparently there is noupper limit to the injection pressure that may be employed except thatimposed by the equipment.

The injection nozzle also serves as a check valve since, when thepressure is lowered, the nozzle closes and the other reactants cannotback into the accelerator mixture feed line. Without such mechanicalsafeguard, the acti vator mixture feed line would quickly become blockedby solid material and the desired mixing operation could not beeffected.

The invention will now further be described with reference to variousforms of apparatus suitable for producing porous and homogeneousplastics, which are illustrated in the accompanying drawings and inwhich:

FIG. 1 is a diagrammatic elevation of an apparatus for mixing thereaction mixture and activator,

FIGS. 2 and 3 are longitudinal sections through reaction devices,

FIG. 4 shows a diagrammatic elevation of an apparatus suitable forcarrying out the modification of the process 7 for mixing two componentsof the reaction mixture and activator,

FIGS. 5, 6 and 7 are longitudinal sections through reaction or mixingdevices for the activator and two compofor mixing the two components ofthe reaction mixture and activator and casting the product,

FIG. 11 is a diagrammatic elevation of equipped with molds,

FIG. 12 is a diagrammatic elevation of an apparatus for producingprofile cords or hollow articles or the like.

Referring now to FIG. 1, an initial liquid reactant mixture ofpolyisocyanate and polyester, charged into tank 1, is passed to a gearpump 2 having a variable number of revolutions, which forces thereaction mixture at any desired rate through a reaction or mixing device3 as illustrated in FIG. 2 or 3. This reaction or mixing deviceessentially consists of a feed pipe 5 for the reaction mixture and aninjection nozzle 4 for the activator component through mittentlyinjected into the continuously flowing initial reaction mixture, eithertransversely to the flowing direction of the initial reactant mixture(see FIG. 3) or in counter current to, the initial reactant mixture (seeFIG. 2). Injection is counter-current to the flow of the initialreactant mixture, wherein the initial reactant mixture is preferablypassed around the nose of the nozzle, has proved to be especiallysuitable. The injection impulses of the a turntable nozzle 4 areeffected by the injection pump 6 (as shown in FIG. 1), which is suppliedwith the activator component from the tank 7. After injection, themixture is forced through a nozzle plate 52 into a chamber 8 into whicha continuous compressed air stream is passed through a tangentialair-pipe connection 9. The air stream effects an intense mixing of thereactive and expansible material, or the mixing operation is performedby means of a mechanically operating stirring equipment (seeFIGS. 5 and7); In the tangential-transverse mixing operation shown in FIG. 3 thereaction mixture enters the ring chamber 54 through the feed pipe 5andis then forced through the slots 55 to the mixing chamber 56, whereintense mixing with the activator mixture intermittently injectedthrough the nozzle 4 is effected. A second mixing operation by air ormechanically is not required.

The product, while still liquid, leaves the chamber in which the secondmixing operation is carried out, and is cross-linked, rapidly or slowly,depending upon the character of the polyester-isocyanate-acceleratorsystem employed, or is cross-linked and expanded. By suitable selectionof the polyisocyanate-polyester mixture employed, the cross-linking andthe blowing action can be accelerated in such a manner thatcross-linkedprofile pieces or finished fomed plastics are promptly obtained afterdischarge of the mixture from the mixing chamber.

FIG. 4 shows an apparatus suitable for carrying out the modification ofthe process in which for instance a polyester containing hydroxylgroups, a diisocyanate and an activator component e.g. an acceleratorand/ or crosslinking agent are all conveyed separately to the reactionor mixing device 10. The polyester is continuously fed from the storagetank 11 into the reaction or mixing de vice by means of the pump 12 andsimultaneously but separately, a polyisocyanate is injected into thereaction or -mixing device'10 from the storage tank-13 intermittently bymeans of the pump 14 and an activator from the storage tank 15intermittently by means of the pump 16.

The reaction or mixing device 10 may be designed in various manners, forinstance as shown in FIGS. 5, 6, 7, 8 and 9.

In the reaction or mixing device shown in FIG. 5, the

which the activator component is intercomponents admitted through thenozzles 17, 18 and 19 are further mixed by means of the stirrers 20,which are in close proximity to the inlets and the outlet of the mixingdevice. Themixture thus obtained leaves the de vice through the outlet21.

In the reaction or mixing device shown in FIG. 6 the componentsinitially mixed by injection through the nozzles 22, 23 and 24 arefinally mixed in the mixing or turbulence chamber 26 by means, of acontinuous aircurrent which is passed in tangentially through the pipe25. The final mixture leaves the turbulence chamber through the outlet27.

FIG. 7 shows a reaction or mixing device wherein the mixing operation iseffected with a stirrer and by means of an air-current admittedtangentially. The components enter the injection chamber 51 separatelythrough the nozzles 28, 29 and 30, they are mixed in this chamber.

by meansof the stirrers 31, which are in close proximity to the inletsand the outlets of the mixing device. forced through the nozzle plate 52into the mixing or turbulence chamber 33, wherein they are finally mixedby the action of an air-current passed in through a tangential air-pipeconnection 32;the mixture leaves the turbulance chamber 33 through theoutlet 34.

FIGS. 8 and 9 show two possible arrangements of the peripherallydisposed nozzles 28., 29 and 30 opening into the reaction device (shownin FIG. 7).

FIG. 10 shows an apparatus for the manufacture of rigid and elasticpolyurethane products, which enables block material to be produced in acontinuous flow, or plastic or foamed plastic foils to be produced on acontinuously travelling conveyor belt. Polyester is conveyed from astationary tank 35 by means of the stationary pump 36 through a flexibletube 37 to a reaction or mixing device 38 (similar to Numeral 10 in FIG.4) mounted on a movable and oscillating carriage 39. A storage tank 40for the isocyanate and a storage tank 41 for the accelerator mixture aremounted on the carriage 39. From the tank 40 the isocyanate is conveyedto the reaction or mixing device 38 by means of an injection pump 42,and from the tank 41 the accelerator mixture is conveyed to the reactionor mixing device 38 by means of an injection pump 43. For the productionof foils, the

final mixture issuing from the mixing chamber is deposited on a conveyorbelt 44 arranged beneath and in close proximity to the carriage 39 andslowly travelling transversely to the moving direction of the carriage39.

The apparatus disclosed in FIGURE 10 is also adapted for use with atwo-component feed system in the continuous manufacture of rigid andelastic polyurethane sheets or blocks or in the continuous production ofplasno or foamed plastic foils on a continuously travelling conveyorbelt. Using a two-component system, the mixture of isocyanate andpolyester, initially charged in tank 35, is continuously conveyedtherefrom by means of a stationary dosing pump 36 through the flexibletube 37 to the reaction or mixing device 38 mounted on a movable andoscillating carriage 39. From the accelerator storage tank 41, alsomounted on carriage 39, the accelerator mixture is conveyed andintermittently injected into the reaction device by means of theinjection pump 43. For the production of foils, the final mixture,issuing from the mixing chamber is deposited on the conveyor belt 44arranged beneath and in close proximity to the carriage 39, which slowlytravels transversely to the movmg direction of the carriage 39.

FIG. 11 shows a device for producing moldings from but not limited byExample I A mixture of 100 parts by volume of a polyester prepared from16 mols of adipic acid, 16 mols of diethylene glycol and 1 mol oftrimethylolpropane, and 25 parts by volume of toluylene diisocyanate ischarged into tank 1 (FIG. 1) and held at a temperature of 27 C. Thismixture is fed continuously to the reaction or mixing device 3 at a rateof 2 liters per minute. The activator mixture consisting of 3 parts byvolume of the adipic acid ester of N-diethylaminoethanol, 2 parts byvolume of ammonium oleate and 1.2 parts by volume of Water is stored intank 7 at a temperature of 18 C. and intermittently injected into thestream of the polyester-isocyanate mixture at a pressure increasing from1470 p.s.i. to 5145 p.s.i. and at a rate of 0.08 liter per minute. Thiscorresponds to a feed rate of 4 parts by volume of activator mixture foreach 100 parts by volume of the isocyanate-polyester mixture andinvolves an injection rate of 1500 injections per minute. Thetemperature rises to 37 C. in the mixing chamber and during the foamingprocess, a temperature of about 100 C. is reached inside the foamingmass. The final elastic foam has a bulk density of 7075 kg./m.

Example 2 100 parts by volume of a polyester prepared from 16 mols ofadipic acid, 16 mols of diethylene glycol and 1 mol oftrimethylolpropane, held at a temperature of 22 C., 47 parts by volumeof toluylene diisocyanate, held at a temperature of 18 C., and parts byvolume of the activator mixer as described below, held at a temperatureof 180 C., are brought together using the apparatus diagrammaticallyrepresented by FIG. 4. The activator mixture consists of 3 parts byvolume of the adipic acid ester of N-diethyl amino ethanol, 1 part byvolume of ammonium oleate, 1.5 parts by volume of sulfonated castor oil,parts by volume of Water and 0.5 part by volume of a paraffin oil. Thepolyester is fed continuously to the reaction or mixing device 10 at arate of 4 liters per minute, the diisocyanate at a rate of 2 liters perminute and the activator mixture at a rate of 0.4 liter per minute,respectively. The diisocyanate and the activator mixture are injectedintermittently using 9000 injections per minute and 3000 injections perminute, respectively. In the mixing chamber the temperature rises to 27C. and in the foaming mass a temperature of 130 C. is reached. The finalelastic foam has a bulk density of 35 kg./m.

Example 3 A rigid foam with a bulk density of 75 l g./m. is producedfrom the following mixture:

50 parts by Weight of a polyester prepared from 2.5 mols of adipic acid,0.5 mol of phthalic acid and 4 mols of trimethylolpropane; 50 parts byweight of a polyester prepared from 3 mols of adipic acid, 1 mol ofhexanetriol and 3 mols of 1,3-butylene glycol; and 10 parts by Weight ofactivated charcoal are mixed and hereinfater referred to as polyestermixture. 1 part by volume of the adipic acid ester ofN-diethylaminoethanol, 1 part by volume of ammonium oleate and 2 partsby volume of sulfonated castor oil are mixed and hereinafter referred toas activator mixture.

100 parts by volume of the polyester mixture, 75

parts by volume of toluylene diisocyanate, and 4 parts by volume of theactivator mixture, held at temperatures of 40 C., 18 C. and 18 C.,respectively, are mixed by means of a reaction of mixing devicediagrammatically represented in FIG. 4. To each 4.5 liters of polyestermixture passing each minute in continuous stream into the reaction ormixing device, 3.4 liters of toluylene disisocyanate and, separately,0.18 liter of activator mixture are injected intermittently at a rate of9-000 and 3000 injections per minute, respectively. The temperaturerises to 27 C. in the mixing chamber and to 180 C. in the foaming massduring the foaming process.

Example 4 A rubber-like elastic polyurethane is obtained in thefollowing Way:

A mixture of parts by voume of a polyester prepared from 11 mols ofethylene glycol and 10 mols of adipic acid with 25 parts by volume of1,5-naphthalenediisocyanate is fed continuously at a temperature of C.and at a rate of 2 liters per minute to a mixing device 3 (FIG. 1). 2parts by volume of butylene glycol are introduced into each parts byvolume of the continuous stream of polester-polyisocyanate mixture at arate of 1500 injections per minute, the butylene glycol serving as across-linking agent. The reaction mixture is cast at a temperature of C.into molds preheated to 100 C. The molding is then heated to 100 C. for24 hours.

Where reference is made in the specification and claims tointermittently or intermittent feed, it is to be understod that theexpressions are intended to designate an injection rate of about 50 toabout 10,000 and preferably about 2,000 to about 10,000 injections perminute.

In addition to the various uses mentioned earlier herein, the productsprepared by the apparatus of the instant invention are useful in all ofthe applications set forth in our application Ser. No. 327,522 referredto above.

We claim:

1. Apparatus for producing porous and homogeneous plastics as desiredfrom components charactrized by rapidly forming a solid product uponmixing, comprising in combination, a substantially enclosed mixer; meansfor introducing into said mixer a continuous stream containing two ofsaid components; means located adjacent to said continuous stream forintermittently and countercurrently injecting under substantial pressureinto said mixer and into said stream measured amounts of another of saidcomponents and thereby effecting substantially instantaneous andintimate mixing of said components; means for conveying said mixedcomponents from said mixer into another mixing chamber wherein continuedmixing of said components is effected by tangential injection ofcompressed air into said chamber and into said mixed components; anddischarge means open to the atmosphere for discharging the resultingmixture while still in a liquid state.

2. Apparatus for producing porous and homogeneous plastics as desiredfrom components characterized by rapidly forming a solid product uponmixing, comprising in combination, a substantially enclosed mixercontaining a stirrer; means for operating said stirrer; means forintroducing into said mixer a continuous stream of one of saidcomponents; a plurality of means for intermittently injecting undersubstantial pressure into said mixer and into said continuous streamwhile operating said stirrer measured amounts of said other componentsand thereby effecting mixing of all of said components; means forconveying said mixed components from said mixer into another mixingchamber wherein further mixing of said components is effected bytangential injection of compressed air into said chamber and into saidmixed components; and discharge means open to the atmosphere fordischarging the final mixture While still in a liquid state, said secondand third mentioned means opening into the upper portion of said mixerat substantially the same level.

2/1956 Atkins 259-8 259-8 2,736,534 2,816,741 12/1957 ShufimanReferences Cited UNITED WILLIAM I. PRICE, Primary Examiner.

STATES PATENTS Wager 299 83 5 LEO QUACKENBUSH, CHARLES -WILLMUT H,Chapman n Examiners. MCGI ihIiH 259-8 H. BERMAN, I. M. BELL, I. C.SOLLENBERGER, Keen 260-25 Assistant Examiners.

2. APPARATUS FOR PRODUCING POROUS AND HOMOGENEOUS PLASTICS AS DESIREDFROM COMPONENTS CHARACTERIZED BY RAPIDLY FORMING A SOLID PRODUCT UPONMIXING, COMPRISING IN COMBINATION, A SUBSTANTIALLY ENCLOSED MIXERCONTAINING A STIRRER; MEANS FOR OPERATING SAID STIRRER; MEANS FORINTRODUCING INTO SAID MIXER A CONTINUOUS STREAM OF ONE SAID COMPONENTS;A PLURALITY OF MEANS FOR INTERMITTENTLY INJECTING UNDER SUBSTANTIALPRESSURE INTO SAID MIXER AND INTO SAID CONTINUOUS STREAM WHILE OPERATINGSAID STIRRER MEASURED AMOUNTS OF SAID OTHER COMPONENTS AND THEREBYEFFECTING MIXING OF ALL OF SAID COMPONENTS; MEANS FOR CONVEYING SAIDMIXED COMPONENTS FROM SAID MIXER INTO ANOTHER MIXING CHAMBER WHEREINFURTHER MIXING OF SAID COMPONENTS IS EFFECTED BY TANGENTIAL INJECTION OFCOMPRESSED AIR INTO SAID CHAMBER AND INTO SAID MIXED COMPONENTS; ANDDISCHARGE MEANS OPEN TO THE ATMOSPHERE FOR DISCHARGING THE FINAL MIXTUREWHILE STILL IN A LIQUID STATE, SAID SECOND AND THIRD MENTIONED MEANSOPENING INTO THE UPPER PORTION OF SAID MIXER AT SUBSTANTIALLY THE SAMELEVEL.